Throughout the 1930s, Abbott and Costello began performing together in burlesque shows, minstrel shows, vaudeville and movie houses.

At Costello's request, all profits earned from the act were split 60/40, favoring Abbott, because, according to Costello, "comics are a dime a dozen. Good straight men are hard to find."

In 1938 they received national exposure for the first time by performing on the Kate Smith[?] Hour radio show, which lead to the duo signing with Universal the following year. Abbot and Costello released their first film in 1940 entitled, One Night in the Tropics. Although Abbott and Costello were only filling supporting roles in the film, they stole the film with their classic routing Who's On First?. (Abbott and Costello are the only two non-baseball players honored in the Baseball Hall of Fame museum in Cooperstown, New York, because of their legendary Who's On First? routine.)

Within a couple of years, the comedy team had also their own television and radio shows.